A Knee's Sweet Sequelae From Uncontrolled Diabetes

HISTORY: 64-year-old male housekeeper with uncontrolled DM2 presents with chronic atraumatic right knee pain below his kneecap. Pain worsens with walking, standing, or climbing stairs and is associated with increased swelling at night. No fever/chills. Prior to symptom onset, he was hospitalized for gangrene of his right 3rd & 4th toes resulting in amputations. His course was complicated by erosive osteomyelitis of his right tibial tuberosity secondary to a right shin abscess. PHYSICAL EXAMINATION: Right knee shows significant swelling around the tibial tubercle without fluctuance; there’s overlying skin hyperpigmentation without erythema, warmth or drainage. Tenderness is elicited over the patella and tibial tuberosity. Positive patellar grind test without joint line tenderness. The knee and ankle have FROM with normal strength. Ligamentous and meniscal testing are normal. The right lower extremity is neurovascularly intact with normal gait. DIFFERENTIAL DIAGNOSIS: Patellar tendinopathy, patellofemoral osteoarthritis, infrapatellar bursitis, Hoffa fat pad impingement TEST AND RESULTS: MRI Right Knee w & wo contrast: Right tibial tubercle cortical erosion, stable from prior hospital CT. Marked thickening, small partial tears, and interstitial tendon splits along the patellar tendon near the tibial tubercle with fibrosis to the overlying subcutaneous soft tissue. Patellar chondromalacia. Medial meniscal tear with mild joint effusion. Sonography: Thickened right patellar tendon ~1.7 cm in AP thickness with mild surrounding edema. Mixed echogenicity with small interstitial tears within the distal tendon. Synovial fluid analysis: No crystals or growth on cultures. FINAL WORKING DIAGNOSIS: Patellar tendinopathy due to prior knee infection. TREATMENT AND OUTCOMES: No improvement with activity modification, NSAIDs, ice, or intraarticular glucocorticoid injection. He was started on isometric and gentle flexibility exercises for quadriceps, hamstrings, and calf muscles before progressive loading eccentric exercises were added. Offered topical nitroglycerin for pain relief. Next option prior to surgical interventions is an ultrasound-guided needle tenotomy. Alternative adjunctive options also include extracorporeal shockwave therapy, platelet-rich plasma, and prolotherapy.